The administration of medicinal agents by inhalation for treatment of diseases of the respiratory tract is known. Such administration has often been accomplished with the aid of compressed air, a propellant gas or the like forming an aerosol effluent to be inhaled. Accurate dosing is difficult and a large proportion of the medicinal agent may go beyond the respiratory tract with undesired side effects. Administration of medicinal agents as an aerosol has also been accomplished by patient inhalation with movable elements serving to atomize the medicaments. In many of these prior devices, the various parts are formed by step by step mechanical manufacture, thus rendering the same relatively expensive to produce. In U.S. Pat. No. 4,046,146, inhalation by the patient serves to create an aerosol effluent without moving parts and with accuracy as to each dosage by employing a metering arrangement for dispensing an accurate dosage to a housing with an internal venturi configuration through the constriction of which air is drawn by inhalation and medicinal agents are delivered in the vicinity of the constriction for passage to a dispenser zone and to an aerosol exhaust section formed as a mouthpiece or nasal appliance from which the effluent is inhaled by the patient.